Investigators believe the truck was heading north on Folsom Boulevard when it went through the center guardrail and onto the southbound side where it slammed into the oak woodlands and a sign outside a Folsom Lake recreation area entrance.

Southbound Folsom Boulevard was shut down until about 9 a.m. between Blue Ravine Road and Natoma Station Drive.

Northbound Folsom Boulevard remained open.

It took paramedics about 20 minutes to get the man out of the twisted metal of the truck. He was later pronounced dead inside the ambulance, the CHP said.